1. Field of the Invention
The present invention relates to the generation of a reducing atmosphere for heat treatment of metals, and more particularly to generating a reducing atmosphere for heat treatment of metals from superadiabatic combustion.
2. Brief Description of the Related Art
Heat treatment of metals has been utilized to improve the properties of metals. For example, U.S. Pat. Nos. 5,284,526, 5,298,090, and 5,417,774, all issued to Garg et al., describe processes for annealing metals in which nitrogen and residual oxygen are passed through a platinum-group catalyst reactor to convert the oxygen to water, and then passing this reaction product along with a hydrocarbon into the heating zone of a continuous furnace. According to Garg, the water is converted to carbon dioxide and hydrogen by water gas shift reaction, and a reducing atmosphere is produced for the heat treatment of metal in the furnace.
Such prior processes suffer from several disadvantages. The requirement for a catalyst in order for the reaction to proceed adds additional costs to the process and apparatus. Furthermore, for many prior processes, the reaction gases must be heated, which further complicates the process and makes the overall process less efficient and significantly more costly. These prior processes are generally concerned with combustion in a fuel-lean reaction.
Metal heat treatment in a controlled atmosphere has previously been described. See, for example, U.S. Pat. Nos. 4,992,113, 5,057,164, 5,069,728, 5,207,839, and 5,242,509, each of which is incorporated in its entirety herein by reference.
In accordance with a first exemplary embodiment in accordance with the present invention, a process of heat treating metal comprises the steps of superadiabatically reacting a hydrocarbon with oxygen to produce hydrogen, and exposing the metal to the hydrogen.
In accordance with a second exemplary embodiment in accordance with the present invention, a system useful for heat treating metal with a reducing atmosphere comprises a superadiabatic reactor having a product gas outlet, and a metal heat treatment apparatus having an inlet in fluid communication with said reactor gas outlet.
Still other objects, features, and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of embodiments constructed in accordance therewith, taken in conjunction with the accompanying drawings.